This invention relates to photographic film with variable windows and, more particularly, to film having increased variability and variety for the taking of photographs. The photographic film makes use of two elongated strips each equipped with photosensitive material for this purpose.
Superposed strips for photographic purposes have long been known--but for different purposes. For example, the difficulty in obtaining focus resulted in the use of transparent portions in film strips as seen in U.S. Pat. No. 1,312,052 of 1919, Austrian Pat. No. 87916 of 1921 and U.S. Pat. No. 1,467,543 of 1923. None of these, however, teach the idea of a photographer using more than one film medium on any one spool of film.
The instant invention addresses the problem that each roll of film used in a camera has only one ASA reading or sensivity speed for light reception. The automatic cameras are set at this ASA reading and the entire roll of film is exposed at this standard. This is determined largely by the limitations of darkroom processing.
In addition to this, the receptive chemicals for each type of developing process must be the same for the entire roll. For instance, color receptive chemicals on one roll, black and white receptive chemicals on another. If the cameraman wants to change his mode of photographing, he must either change cameras or change the roll of photographic film.